I have a 308Win chambered M90. The M90 is a postban version of the M77 that came with a thumbhole stock. I converted mine to the proper pistol grip configuration using an Ironwood stock set and Tapco G2 trigger group. It's now exactly as it should be.

I'm glad to see that they are (sort of) available again. If I didn't have one already, I'd wait to see if Century imports some in the correct double stack magazine configuration without the slant cut at the rear of the receiver. They're doing this already with their 7.62x39 rifles and 308Win Vepr's are being imported this way, so I don't see what would prevent Century from importing them this way

I really want a new M77, but I am going to wait till Black Friday. The hammer forged 20" barrel and adjustable gas system are huge selling points. I wish they thought the scope rail out a little bit though, having a scope rail that far back makes it worthless. I wish it didn't even have a rail on it!

You know what? I think I'm wrong. I looked at the picture on Aim's website and thought it was a single stack magazine. Now looking at it a little close, it must be a double stack because it's 10rds. If it was a single stack 10rd mag, then it would have to be as long as the 20rd mag in my rifle.

Will they work in the original 308Win chambered M77's or the M90's (like mine pictured above)?

I wish I owned one of the original rifles so I can test the fit & function of the new 10rd magazines!
The picture I posted is of an actual new magazine.
How does it compare with the older 20rd magazines?

It pretty much looks the same, but shorter. I'm surprised that the angle of the floor plate on the 10rd mag looks to be the same as the angle of the floor plate on the 20rd mag. I'd think that it would be about half as much. The thing that concerns me is the magazine catch tab. It might be thinner on the 10rd mag. This would be the case if the rifle was setup to only accept 10rd mags. If you want to send me one I'll let you know and can take pictures of the differences (if any). Of course I'll pay for it if it works and will send it back if it doesn't.